Two university hospitals are developing new ways to preserve the hearts that are transplanted to adult and babies patients, so that some donations that are very difficult to take advantage of with current technology can be used.
New research seeks to take advantage of the organs of people who die when their heart stops beating. Called as a donation after circulatory death (DCD, in English), it implies a controversial recovery technique or the use of expensive machines.
Doctors from the universities of Duke and Vanderbilt reported on Wednesday that they have devised simpler methods to take advantage of those hearts. In an article published in the scientific journal New England Journal of Medicine described the successful transplant of hearts to a 3 -month -old baby in Duke and three men in Vanderbilt.
“These DCD hearts work as well as the donor hearts with brain death,” said Aaron M. Williams, lead author of the Vanderbilt article and academic.
How hearts are preserved for donation
Most transplanted hearts come from donors with brain death. In those cases, the body connected to a respirator that keeps the heart beating is maintained until the organs are extracted.
Circulatory death occurs when someone suffers a brain injury incompatible with life, but since not all brain functions have ceased, the family decides to remove life support and the heart stops. This means that organs can spend time without oxygen before being recovered, a period of time that is usually viable for kidneys and other organs, but that can raise doubts about the quality of hearts.
To counteract the damage and determine if the DCD organs are usable, surgeons can pump blood and oxygen to the abdominal and thoracic organs of the deceased donor, after blocking access to the brain. However, it is ethically controversial to artificially restore the circulation, even temporarily, and some hospitals prohibit that technique, called regional normothermal or NRP regional perfusion.
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Another option is to “revive” the DCD organs in a machine that pumps blood and nutrients during the transfer to the transplant hospital. The machines are expensive and complex, and Dr. Joseph Turek, from Duke, said the devices cannot be used for the small hearts of young children, the age group with the greatest need.
New ways to preserve hearts
Turek’s team found a middle ground: extract the heart and connect oxygen and blood tubes to briefly evaluate its functioning capacity, not in a machine, but at a sterile table in the operating room.
They practiced with piglets. Then the real test arrived. In another hospital, the life support was going to be withdrawn to a one -month -old baby whose family wanted to donate it, and that would be compatible with a three -month -old Duke patient who desperately needed a new heart. The other hospital did not allow the controversial NRP recovery technique, but let the Turek team prove the experimental alternative.
It only took five minutes to determine that “the coronary arteries are filling well, it is pink, it is beating,” Turek said. The team quickly put the little heart on ice and quickly took Duke.
The Vanderbilt system is even easier: a cold preservative solution rich in nutrients is infused in the heart before extracting it from the donor’s body, similar to how donor hearts with brain death are manipulated.
That “replenishes the nutrients that are exhausted during the death process and helps protect it for transport,” Williams explained, adding that Vanderbilt has so far performed about 25 transplants of this type. “Our opinion is that it is not necessary to revive the heart.”
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More hearts are needed
There is a great need for more transplantable hearts. Hundreds of thousands of adults suffer advanced heart failure, but many are not even offered a transplant due to organ scarcity.
Every year, around 700 children in the United States are added to the list of transplants to receive a new heart and about 20 % die while waiting. Turek said babies run a special risk.
Last year, people whose life ended by circulatory death represented 43 % of the deceased donors of the country, but only 793 of 4,572 heart transplants.
Therefore, many specialists claim that it is essential to find ways to use more of those hearts. The new studies are small and are in an initial phase, but they are promising, according to Brendan Parent, by Nyu Langone Health, who directs research on ethics and transplant policies.
“Innovation to find ways to recover organs successfully after circulatory death is essential to reduce organ scarcity,” he said.
If the alternatives work, “I am convinced that cardiac programs will be delighted, especially in hospitals that have rejected the NRP.”
